Dobby knife guide



July l2, 1938,

R. G. TURNER BOBBY KNIFE GUIDE Filed Sept. 24, 1937 2 Sheets-Sheet 2 Inveror Rmhavd Cr.Tumer AH'or ey Patented July 12, 1938 UNITED sTAEs BOBBY KNIFE GUIDE Richard G. Turner, Worcester, Mass., assignor to Crompton & Knowles Loom Works, Worcester, Mass., a corporation of Massachusetts Application September 24, `193'?, Serial No. 165,544

6 Claims.

This invention relates to improvements in loom dobbies and it is the general object of the invention to prevent objectionable endwise motion of the harness liftingknives relatively to the hooks during the working and return strokes of the knives.

Loom dobbies customarily includeA a pair of i spaced oppositely reciprocating knives which cooperate with hooks pivoted to dobby levers and 10 controlled by pattern mechanism. The levers in turn are connected to harness jacks which lift the corresponding harness when the associated hook is moved outwardly by a knife. Because of the shedding conditions necessary for the warp threads the rear harness frames aremoved through a greater vertical distance than are the front frames and in order to eifect this difference in motion the dobby knives swing from one oblique position at the beginning of their working stroke 20 to an oppositely inclined oblique position at the end of their working stroke, the greater travel being at the rear end of the knife.

When the load on the dobby is considerable due to` an increased shed or a heavy warp the pres- 25 sures existing between the hooks and the knives i-s suflicient to cause an end motion of the knives transversely of the hooks. This end motion strains the connectors between the knives and their rocking levers and interferes with efcient running of the dobby.

It is an important object of my present invention to provide guides for the dobby knives effective preferably throughout the working and re` turning strokes of the `knives to prevent substantial end motion thereof by means of cooperating parts certain of whichare on the knives and others of which are fixed to the dobby frame. In

the preferred form of my invention I provide slotted guides substantially parallel to the hooks 40 to receive lugs or the like on the knives.

With these and other objects in view which will appear as the description proceeds, my invention resides in the combination and arrangement of parts hereinafter described and set forth.

45 In the accompanying drawings, wherein a convenient embodiment of my invention is setforth,

Fig. 1 is a front elevation of a dobby made according to my present invention, y

Fig. 2 is a plan view looking in the direction o 50 arrow 2, Fig. l, showing the guide for the top knife,

Fig. 3 is a horizontal section on line 3-3 of Fig. 1 showing the guide for the lower knife,

Fig. 4 is a vertical section Online 4--4 of Fig. 1

55 showing the guide for the lower knife and Fig. 5 is a diagrammatic plan showing the various angular relations of the knife with respect to the dobby Darts.

Referring to the drawings, the dobby D has front and back side plates ID and I I, respectively, l and is provided with va set of harness lifting jacks I2 pivoted as at I3. Each jack is pivoted to a dobby lever I4 positioned by upper and lower back .girts I 5 and I 6, respectively. Each lever Iii has pivoted at the upper end thereof a top hook I1 while the lower end is pivoted to a bottom hook IB. Guide racks or combs I9 space the hooks and hold them in proper position relatively to hook lifters not shown.

rThe dobby is provided with front and back 15.

rocker or actuator levers 2l) and 2|, respectively,` the rear lever having a third arm 22 which receives a rocking motion from a vertically reciprocating rod 23. The latter may be driven in any approved manner and receives an up stroke on one beat of the loom and a down stroke on the next beat so that two complete beats of the loom are necessary for the cycle of the dobby.

The upper and lower ends of each of the levers 2li and 2l is attached to a connector C which 2,5 has a rod 25 having a hub 26 to receive a stud 21 carried by the lever. The outer end of the connector has passing therethrough a pin 28 which also passes through a bearing block 29 through which extends the gudgeon 3D of a knife K. The 30 connection between the pin 28, bearing 29 and connector 25 is such as to permit relative movement of the knife in a horizontal plane with respect to the plane of action ofthe rocker levers, while the hub 26 accommodates the rise and fall 1 of the levers 2li and 2| as they rock about their common axis 32. Bearing 29 may also slide off gudgeon 30 to a limited extent. The frames I0 and II have guide slots which receive` slide bearings 36 formed on the knives K, the slots 35 .40 being sufficiently long to permit the knives to have their outward working and inward return strokes.

During the operation of the dobby as thus far described rising of the rod 23 will cause the upper 4-5 knife to move outwardly away from the jacks I2 at which time any of the upper hooks I'I which nave been indicated for engagement with said knife will be moved outwardly tol have a harness lifting motion. At the same time the lower knife will move inwardly or toward the jacks I2. On the nextV beat the direction of knife motion will be reversed and any of the lower hooks I8 which have been indicated for engagement with the bottom knife will be moved outwardly to lift or maintain in raised position the associated harness frame.

The matter thus far described is of common construction and operates as does the usual dobby. It is found as a result of. heavy loading of the dobby that the knives have a tendency to move endwise or laterally with respect to the hooks II and I 8. This is particularly true at the ends of the stroke as will be seen from Fig. 5 where position a represents the` knife as inclined rearwardly and toward the center of the loom at the beginning of its working stroke, the upper part of Fig. 5 being toward the rear of the loom. Position b shown in dotted lines represents an intermediate position of the knife when the same is substantially perpendicular to the hooks, while position c shown in dot and dash lines represents the end of the outward or working stroke of the knife at Whichtimethelatterisinclined rearwardly and away from the center of the loom. Then the knives are in the position shown at a or c in Fig. 5

l they are subjected to an end thrust because of their angular position, this thrust exerting side strains on the connectors C and also tending to move the hooks against the racks I9.

In carrying my present invention into effect I provide guide means for the top and bottom knives so constructed as to provide a guide slot extending in a direction generally parallel to the hooks and fit into said slot a lug or the like carried by the associated knife.

As shown in Figs. 1 and 2 the guide 50 for the upper knife has a slot 5I into which ts a depending lug 52 carried by the top knife. Guide 5G has inner and outer feet 53 and 54, respectively, which are secured to cross girts one of which is a part of the upper rack I9 and the other of which is provided for the purpose and designated at 55. These cross girts hold the guide 59 so that the slot 5I is substantially parallel to the working stroke of the knife K.

The guide for the loWer knife is shown particularly in Figs. 3 and 4. As in the case of the upper knife there is a guide 60 similar to guide 55 and having a guide slot 6I to receive a lug 62 which, however, in this instance is not connected directly to the bottom knife. 'I'he guide 60 has inner and outer feet 63 and 64 which are connected to the lower rack I9 and an auxiliary girt 65 provided for the purpose and extending between the side plates IIJ and II and secured thereto.

In order to provide a mounting for the lug 62 I extend upwardly from each end of the lower knife a boss 'I0 and bridge said bosses by a cross bar 'II secured to the bosses and having the lug 62 secured thereto. The cross bar 'II is sufficiently high to permit the necessary vertical motion of the lower hooks I8 under action of the pattern mechanism not shown.

In operation, theguide slots 5I and 6I are preferably located half way between and parallel to the side frames I0 and I I. As the knife starts from the position a in Fig. 5 the lug 52 or 62, depending upon which knife is rearmost, Will be at the inner end of the slot, and as the knife moves outwardly on its Working stroke in a direction substantially parallel to the frames I0 and II it will change its angular position, passing through the position b and ultimately reaching the position of c. Through practically the Whole of this motion the lugs move in the guide slots and prevent substantial end motion of the knives with the result that the strains exerted between the hooks and the knives due to the angular position of the latter are not permitted to reach the connectors 25.

From the foregoing it will be seen that I have provided a loom dobby with guides for the knives so constructed as to prevent substantial end motion of the knives in a direction transverse of the hooks. It will further be seen that these guides may preferably lie intermediate the side plates I0 and II and include slots parallel to the working stroke of the knives and proportioned to receive lugs or the like moving with the knives and cooperating with the guides to prevent said end motion of the knives, preferably throughout the stroke of the knives.

Having thus described my invention it will be seen that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention and I do not wish to be limited to the details herein disclosed, but what I claim is:

l. In a loom dobby having spaced substantially parallel side frames, a set of hooks between and substantially parallel to said frames, a knife supported by and movable along the frames, means to move said knife in a direction substantially parallel to said hooks and at the same time change the angular relation of said knife relatively to the hooks, and a pair of cooperating members to resist endwise motion of the knife laterally of the hooks, one of said members having a slot substantially parallel to the side frames to receive the other member, one member being fixed to the knife and the other member being xed With respect to the dobby.

2. In a loom dobby having spaced substantially parallel side frames, a set of hooks between and substantially parallel to said frames, a knife supported by and movable along the frames, means to move said knife in a direction substantially parallel to said hooks and at the same time change the angular relation of said knife relatively to the hooks, and a pair of members cooperating with each other continuously throughout the motion of the knife to prevent endwise motion thereof in a direction transverse of the hooks, one of said members having a slot substantially parallel to the side frames to receive the other member, one of said members being on the knife and the other of said members being fixed with respect to the frames.

3. In a loom dobby having spaced substantially parallel side frames, a set of hooks between and substantially parallel to said frames, a knife supported by and movable along the frames, means to move said knife in a direction substantially parallel to said hooks and at the same time change the angular relation of said knife relatively to the hooks, and a pair of cooperating members to prevent substantial endwise motion of the knife in a direction transverse of the hooks, one of said members carried by the knife and the other of said members supported by the frames, and one of said members having a slot which remains substantially parallel to the side frames throughout the motion of the knife and receives the other member.

4. In a loom dobby having spaced substantially parallel side frames, a set of hooks between and substantially parallel to said frames, a knife supported by and movable along the frames, means to move said knife in a direction substantially parallel to saidihooks and at the same time' changeV the angular relation of said knife relatively to the hooks, a guide located between the side'frames, and a second guide on the knife located between the side frames, one of said guides having a slot substantially parallel to the side frames into which the other guide fits, said guides cooperating with each other to prevent substantial endwise motion of the knife laterally of the hooks as said knife moves.

5. In a loom dobby having spaced substantially parallel side frames, a set of hooks between and substantially parallel to said frames, a knife supported by and movable along the frames, means to move said knife in a direction substantially parallel tosaid hooks and at the same time 4change the angular relation of saidlknife relatively to the hooks, a guide located between the side frames and having a guide slot substantially parallel to said frames, and a member formed on the knife to enter the slot and cooperate with said guide to resist motion of the knife laterally with respect to the hooks as said knife moves.

6. In a loom dobby having spaced substantial- -ly parallel side frames, a set of hooks between and substantially parallel to said frames, a knife supported. by and movable along the frames, means to move said knife in a direction substantially parallel to said hooks and at the same time change the angular relation of said knife relatively to the hooks, a guide fixed with respect to the dobby `and having therein a guide slot located between and substantially parallel to the side frame, and a member projecting from the knife in a direction transverse of the plane in which the knife moves to enter said slot and cooperate with said guide to prevent endwise motion of the knife transversely of the hooks.

RICHARD G. TURNER. 

